Sergey Sarvadiy

• Ph.D.
• Researcher at N.N. Semenov Federal Research Center for Chemical Physics of Russian Academy of Sciences (FRCCP RAS)

Процессы взаимодействия газообразных реагентов с образованными из наночастиц металлов покрытиями, нанесенными на пиролитический графит, исследованы методами сканирующей туннельной микроскопии и спектроскопии. Показано, что физические и химические свойства области контакта наночастиц с подложкой и области наиболее удаленной от нее могут различаться....

С помощью моделирования в рамках теории функционала плотности адсорбции атомарных кислорода и водорода на поверхности наночастиц палладия на подложках графита с различными дефектами были рассчитаны энергии связи адатомов и изменения плотности состояний атомов металла при взаимодействии с адатомами. Установлено, что энергетическая стабильность адсор...

In this work, we studied the local adsorption properties of gold, nickel, and platinum nanoparticles. A correlation was established between the chemical properties of massive and nanosized particles of these metals. The formation of a stable adsorption complex M-Aads on the nanoparticles’ surface was described. It was shown that the difference in l...

Zeolites are versatile materials of great importance in different areas of science and technology. Due to their physical structure and electronic properties, zeolites possess the ability to selectively adsorb certain chemical compounds from complex mixtures. For this reason, zeolites are used in the development of very sensitive sensors for the det...

Quartz crystal microbalances (QCMs) are devices that have been proven to function as sensors for detecting specific chemical species; this usually requires that the QCM is modified with a material that is capable to interact with the desired compound. Zeolites are an example of materials used as sensitive layer. This due to their capacity for selec...

The oxidation of Ni nanoparticles supported on highly oriented pyrolytic graphite was investigated under conditions of low exposure to oxygen by methods of scanning tunneling microscopy and spectroscopy. It was found that charge transfer effects at the Ni-C interface influenced the surface activity of the nanoparticles. The O2 dissociation and the...

Using the method of quantum-chemical modeling of a system of gold nanoparticles on a graphite substrate with various defects, a decrease in the density of states of gold atoms during the adsorption of hydrogen near the interface is shown. Substrate defects, such as vacancies and cutoffs of the graphene plane, contribute to a decrease in the density...

The hydrogenation features of gold nanoparticles deposited on highly oriented pyrolytic graphite were determined, and composite nanostructures consisting of pure and hydrogenized gold were synthesized. Methods of scanning tunneling microscopy and spectroscopy have been successfully used to probe the bottom of the conductive band and to determine th...

The adsorption of CO on the surface of Cu-based nanoparticles was studied in the presence of an external electric field by means of scanning tunneling microscopy (STM) and spectroscopy (STS). Nanoparticles were synthesized on the surface of a graphite support by the impregnation–precipitation method. The chemical composition of the surface of the n...

In this work, the integration of various elements was realized. This allowed the development of a measurement system for quantitative determination of the electrical response of the faujasite-modified QCM, which was caused by a change in mass during the adsorption and desorption processes. The nanostructured faujasite film was grown on the QCM surf...

The morphologies and local electronic structures of titanium coatings deposited on the surfaces of highly oriented pyrolytic graphite were determined. Chemical compositions of the oxides formed on the coating surfaces were established. A theoretical model was developed describing the changes in the TiOx oxides (1.75 < x < 2) band gap depending on t...

Представлены результаты масс-спектрометрического исследования токсичных химических веществ – хлоруксусных кислот (монохлоруксусная, дихлоруксусная, трихлоруксусная кислоты) и пиридина с применением напуска исследованных веществ в виде модулированного молекулярного пучка. Преимуществом молекулярно-пучкового напуска является сведение к минимуму образ...

Гидрирование наночастиц может являться ключевой стадией обезвреживания опасных химических веществ, в том числе монооксида углерода. В работе представлены результаты квантово-химического моделирования процесса гидрирования золотых и биметаллических золото-медных наночастиц на примере их взаимодействия с атомарным водородом при варьировании элементно...

The results of evaluating the adhesion strength and mechanical characteristics of elementary filaments used to make LUP carbon tape after metal plating the tape with titanium and stainless steel are presented. The thickness of these coatings is determined by atomic force microscopy and also by measuring the diameter of filaments before and after me...

The features of deuterium adsorption on the surface of gold nanoparticles deposited on highly oriented pyrolytic graphite (HOPG) were determined. The results showed that deuterium adsorption on gold nanoparticles takes place at room temperature. The results also showed that the filling of the nanoparticles’ surfaces with the adsorbate occurs from t...

The morphology of two-component nanocatalysts formed by organoboron nanoparticles and platinum nanoparticles deposited on the surface of highly orientated pyrolytic graphite (HOPG) was determined by scanning tunneling microscopy and atomic force microscopy. The electron structure and conductivity of the nanoparticles of the coatings were determined...

In this work, the characteristic features of the morphology and electronic structure of the oxide layer of a titanium coating synthesized on the surface of highly oriented pyrolytic graphite are determined with high spatial resolution. It is found that interaction with oxygen leads to the formation of an oxide TiOx, where 1.75 < x < 2. A possibilit...

This paper presents the results of quantum chemical simulation and experiments to determine the effects of the adsorption of hydrogen onto gold–nickel nanoparticles. Numerical experiments revealed that the most energetically favorable positions of adsorbed hydrogen atoms are mainly located in the vicinity of gold atoms due to electron density redis...

An experimental study of molecular hydrogen adsorption on single gold nanoparticles of various sizes deposited on the surface of highly oriented pyrolytic graphite (HOPG) was carried out by means of scanning tunneling microscopy and spectroscopy. The effect of size on the HOPG/Au system was established. Hydrogen was dissociatively chemisorbed on th...

The adsorption of hydrogen on the surface of gold nanoparticles deposited on a graphite support was studied in the presence of an external electric field by means of scanning tunneling microscopy (STM) and spectroscopy (STS). Hydrogen was adsorbed from the gas phase onto the surface of gold nanoparticles synthesized by impregnation-precipitation me...

The paper presents results of studying structural and physical characteristics of nickel nanoparticles deposited on supports of graphite, silicon, aluminum, and titanium. Adsorption properties of the nanostructured compositions have been investigated with respect to hydrogen and water molecules. Properties of the nanostructured systems have been ex...

The results of studying adsorption properties of single gold nanoparticles deposited on substrates of different nature (i.e. graphite, silicon, aluminum and titanium oxides) in regard to Н2, О2 and Н2О molecules are presented. Adsorption forms, as well as the values of adhesion coefficients and binding energy for the above reagents have been determ...

Method of complex diagnosis of physical and chemical properties of nanostructured coatings dased on single nanoparticles of metals and metal oxides by means of scanning tunneling microscopy and spectroscopy

Morphology and electronic structure of mono- and bicomponent coatings based on platinum nanoparticles and organoboron nanoparticles (OBN) on HOPG have been studied. The bi-component coating is a branched structure formed by agglomerations from clusters of nanoparticles.The results of topographic measurements indicate that this method of creating tw...

Using quantum chemical modeling in the framework of the DFT theory, it was shown that the electronic states density of the Au13C138 supercluster is most significantly reduced near the Fermi level due to adsorption of hydrogen at the gold-carbon interface. The result corresponds to our experimental data.

The results of a study of the interaction of H2, O2, and CO with single nanoparticles of gold and oxidized nickel forming a two-component coating on graphite are given. It is established that hydrogen and carbon monoxide may form HCO particles on the surface of gold and not on the surface of nickel, and these particles are able later to migrate and...

The parameters of deuterium adsorption on the surface of gold nanoparticles supported onto highly oriented pyrolytic graphite were determined. It was established that surface coverage with the adsorbate at a level of single nanoparticles began at a graphite–gold interface; thereafter, the entire surface was filled.

The titanium-based coating was deposited on the surface of the plate of highly oriented pyrolytic graphite by method of thermoresistive evaporation in vacuum, and then exposed to atmospheric oxygen. The coating thus synthesized was investigated by means of atomic force microscopy and scanning tunneling microscopy and spectroscopy. Specific features...

Some physicochemical properties of homogeneous and heterogeneous films formed by Au and Cu nanoparticles on graphite are studied by scanning tunneling microscopy and spectroscopy. It is found that the nanoparticles have a shape close to spherical with a diameter of 3‒6 nm, the gold particles do not contain impurities, and the copper particles can b...

Свойства каталитической системы, состоящей из наночастицы и покрытой слоем оксида проводящей подложки, на которой она расположена, можно контролировать за счёт изменения толщины оксидного слоя. Толщина оксидного слоя определяет эффективность переноса заряда между подложкой и наночастицами и, соответственно, влияет на механизмы протекающих химически...

The paper presents the results of quantum-chemical modeling of gold and copper nanoparticles and a comparison of their adsorption properties with the example of interaction with hydrogen atoms. The goals of the work were both a fundamental study of the electronic structure and the elementary act of the heterogeneous catalysis reaction and the compa...

The shapes, sizes, and electronic structures of platinum nanoparticles supported onto highly oriented pyrolytic graphite and oxidized silicon by different methods and their adsorptive properties with respect to hydrogen, oxygen, water, and ammonia were established. The apparent activation energy of the reduction of single oxidized platinum nanopart...

The adsorption and interaction of hydrogen, carbon monoxide, and oxygen with gold and nickel nanoparticles is studied by scanning tunneling microscopy and spectroscopy. It is established that the HCO radical is formed on gold nanoparticles by the reaction between adsorbed H2 and CO, which is subsequently oxidized by oxygen to water and CO2. At the...

The coatings based on organoboron and platinum nanoparticles deposited on the surface of highly oriented pyrolytic graphite are of special interest as model catalytic systems. In this work, the methods of scanning tunneling microscopy and atomic force microscopy are applied for determining morphology of three kinds of coatings, i.e. based on organo...

Using scanning tunneling microscopy, we have studied the processes of adsorption and interaction of hydrogen, oxygen, and carbon monoxide on the surface of gold nanoparticles and nickel that form singleand bicomponent coatings on graphite. On the gold nanoparticles, the interaction of H2 and CO results in the formation of formyl radicals (HCO•) tha...

The morphology and electronic structure of copper nanoparticles synthesized on the surface of highly oriented pyrolytic graphite by substrate impregnation with a precursor solution and thermoresistive vacuum evaporation have been studied by atomic force microscopy, scanning tunneling microscopy, and scanning tunneling spectroscopy.

Hydrogen interaction with gold nanoparticles deposited on the surface of a highly oriented pyrolytic graphite is determined by the external potential ϕ of the sample with respect to the ground. It is demonstrated that, at ϕ > +1 V, molecular hydrogen does not practically interacts with hydrogen, whereas at ϕ ≤ 0 V, such interaction is possible.

The morphology of bimetallic coating formed in vacuum on the graphite surface at a high-temperature decomposition of HAuCl4 and Ni(NO3)2 has been found. The procedure of applying the precursors onto the substrate required for the formation of nanoparticles has been determined. The features of interaction of hydrogen and oxygen on the gold–nickel co...

The catalytic decomposition of ammonia on (C2B10H4)n composition organoboron nanoparticles deposited on the substrates of SiO2, Al2O3, and highly ordered pyrolytic graphite at T = 750 K and p = 1 × 10–6 Torr is investigated. It is found that the substrate material has a significant effect on the rate of decomposition of NH3. Replacing the SiO2 subs...

The adsorption of hydrogen on nickel nanoparticles (NPs) deposited on the surface of highly oriented pyrolytic graphite by laser electrodispersion and by precipitation from colloidal dispersion has been studied by scanning tunneling microscopy and spectroscopy, as well as by Auger spectroscopy. The elemental composition of the NPs, structure, elect...

Nickel nanoparticles were deposited on the surface of highly oriented pyrolytical graphite by laser electrodispersion and precipitation from a solution of reverse micelles. The particles were studied using scanning tunneling microscopy and spectroscopy as well as Auger spectroscopy. The elemental composition of the nanoparticles and specific featur...

The morphological features of nanostructured films of tin, zinc, indium, and cerium oxides are established. The parameters of electron traps, such as adsorbed oxygen atoms and structural defects, responsible for the sensory effect are determined. An increase in the conductance of indium oxide films upon annealing in vacuum is revealed.

The morphological features of nanostructured films of tin, zinc, indium, and cerium oxides are established. The parameters of electron traps, such as adsorbed oxygen atoms and structural defects, responsible for the sensory effect are determined. An increase in the conductance of indium oxide films upon annealing in vacuum is revealed.